| 摘要 |
PURPOSE:To manufacture high tension steel having superior stress corrosion cracking resistance and high yield strength, by applying hot rolling and heat treatment under specified conditions to steel slab contg. specified compsn. quantities of C, Si, Mn, Ni, Mo, Nb and limited quantities of P, O, N. CONSTITUTION:Steel slab composed of, by weight 0.05-0.10% C, <=0.20% Si, 0.4-1.5% Mn, 5-12% Ni, 0.3-1.5% Mo, 0.005-0.05% Nb, regulated quantities of <=0.010% P, <=0.0025% O, <=0.0040% N, further if necessary >=one kind among 0.2-1.5% Cu, <=0.60% Cr, 0.02-0.12% V, <=0.08% Total Al, 0.005-0.01% Ti, <=0.003% Ca and the balance Fe with inevitable impurity is heated to 1,050-1,250 deg.C, hot rolled, then the plate is water cooled from temp. of >=Ar3 point, the cooling is stopped at <=100 deg.C, then it is tempered at <=600 deg.C. In this way, the titled steel plate is obtd. |
